The invention relates to a process and to an apparatus for the continuous electrolytic treatment and/or coating of a moving metallic strip whilst changing the spacing between the strip and at least one electrode as a function of deviations (distortions) of the strip normal to the direction of movement of the strip.
In general it is desired to maintain the smallest possible spacing between the electrode and the strip in order to keep the voltage drop in the electrolyte small and to save energy. However, if the spacing is set too small, distortions of the strip may result in short circuits and in damage to the electrodes.
An apparatus for changing the spacing between the electrode and the strip is known from U.S. Pat. No. 4,378,284. In that case the electrode is fitted to an electrode mounting means made of elastic tubes, the tubes being filled with a liquid medium, e.g. oil, and the spacing being modified by changing the pressure of the liquid medium. The adjustment of the spacing takes place depending on the operating conditions which affect the efficiency of the electrolysis procedure. For example, holes or slots may be provided in the terminal regions of the strip which are responded to by optical or electrical means to bring about a definite change of the spacing.
Japanese published specification No. 113399 also describes a process for the automatic adjustment of the spacing of the electrode in relation to the strip. However, in that case the adjustment proceeds as a function of the level of consumption H of the anode, the number of ampere hours A.times.N, a constant K and an adjustment factor N for the size of the electrode.